A claim has been received for the £55 million EuroMillions jackpot prize won in Tuesday's draw, Camelot has confirmed.
The lottery operator said the claim will now go through the usual validation process before any prize is paid out.
A single UK ticketholder scooped the £55,013,819 jackpot in the draw on June 20.
Once the ticket has been validated and paid, the ticketholder will decide whether or not to go public and share their news.
Andy Carter, senior winners' advisor at The National Lottery, said: "This is absolutely incredible news and we're delighted that we've received a claim.
"Our focus is now on supporting the ticketholder through the process and helping them start to enjoy their truly life-changing win."
It is the second UK EuroMillions jackpot win this month after one lucky ticketholder scooped the entire £111.7 million jackpot on June 2, the 12th largest sum ever.
In July last year, an anonymous UK ticketholder won a record jackpot of £195 million.